Which type of selector is least specific?

The element selector is considered the least specific type of selector in CSS. This is because it targets all instances of a particular HTML element, applying styles universally to all occurrences of that element within the document.

For example, if you use an element selector like p, it will style every <p> (paragraph) tag in the HTML, regardless of its position or the unique characteristics of the paragraph itself or its context. The lack of specificity means that styles from the element selector can easily be overridden by more specific selectors, such as class or ID selectors. Class selectors, for instance, can apply styles to specific groups of elements or instances identified by the class attribute, while ID selectors target a single, unique element, making them more specific. Similarly, attribute selectors apply styles to elements based on specific attributes they possess, but these selectors also have more specificity than an element selector.

Understanding the concept of selector specificity is crucial for effective CSS development, as it influences which styles are applied when there are competing rules. The element selector's broad application and lower specificity make it a foundational tool in CSS design, even as developers often rely on more specific selectors for precise styling.